Electron–phonon coupling at surfaces and interfaces

Abstract

Over the recent years, electronic surface states have been used for a detailed spectroscopic study of the electron–phonon (e–ph) interaction, both experimentally and theoretically. This review discusses the basic physics of e–ph coupling and how information can be obtained from angle-resolved photoemission experiments and first principles calculations. Several recent results for clean and adsorbate-covered surfaces, quantum wells and free-standing monolayers are also discussed.

Finding the bare band: Electron coupling to two phonon modes in potassium-doped graphene on Ir(111)

“…The two forms of ReΣ(E) are then compared, and the coefficients of the polynomial adjusted until the difference is minimal. 20,21,27,28 In this work we propose a simpler procedure, that avoids the need for a minimization of a functional, and achieves the self-consistency in just a few iterations. The procedure also appears to be more stable with respect to the noise present in the experimental data, and no denoising 27 or smoothing by fitting to a function 15 is needed.…”

“…19 Some other procedures rely on the bare-band dispersion. 20 The choice of the bare-band may, however, influence an accurate determination of the magnitude and shape of the self-energy. 21 A self-consistent GW approximation was applied in ab-initio density functional theory (DFT) calculation to model graphene's bare band that includes all electron-electron correlations.…”

Kinks in theσBand of Graphene Induced by Electron-Phonon Coupling

“…The observation of a kink signals a strong change in the real part of the self-energy AE 0 that describes the deviation of the observed dispersion from the single-particle picture [10]. The origin of this structure can most easily be understood by considering the imaginary part of the self-energy AE 00 that is inversely proportional to the lifetime of the ARPES photohole and related to AE 0 via a KramersKronig transformation.…”

“…E , this is no longer possible, leading to a marked increase in lifetime. The corresponding decrease in AE 00 leads to a maximum in AE 0 , and this gives rise to the kink [10].…”

Enhanced electron-phonon coupling at the Au/Mo(112) surface

“…The former includes lowtemperature electronic heat capacity and finite electrical conductivity. The latter ranges from surface reconstructions to superconducting phase transitions [2,3]. Although the electron-phonon coupling is ubiquitous, due to the low excitation energy of phonons (typically <100 meV for metals), its effect on the electronic structure is most pronounced in the vicinity of Fermi level (E F ).…”